1. Field of the Invention
The present invention relates to a leak detector for a pipe connection, and more particularly a leak detector for a pipe connection in a visually obstructed location.
2. Description of the Related Art
Seal integrity between adjacent flanged pipes is of primary importance in a fluid filled system. A seal is typically maintained by a gasket retained in position inside the flange bolting.
A gasket used to seal adjacent pipes is subject to warping and damaging stresses. It may be exposed to temperature extremes or the corrosive effects of the fluid within the pipe. Such conditions promote deterioration of the material of the gasket and can lead to failure of the seal with subsequent leakage of the fluid from the pipe to the exterior. Leakage can occur at any point around the circumference of the pipe joint. The leaking fluid will thus contaminate the bolts of the flange joint and may, depending upon its properties, corrode the structure of the pipe joint itself.
Thus, it is important that any leakage is detected, contained and repaired quickly. Early detection of leaks avoids more serious problems caused to the pipe structures and surroundings that may occur if leaks remain undetected until a relatively late stage.
Leaks from pipe connections in residential and commercial properties is a significant source of property damage. Specifically, the piped connections to wastewater plumbing fixtures such as toilets, bathtubs, standing showers, sinks and the like, are often obstructed from view and leaks can go undetected until water seepage has caused structural damage such as floor deterioration and mold growth. An undetected leaks from a toilet drain pipe connection is a common problem.
In toilets waste water exits to a flanged drain pipe in a bathroom floor. Toilets are typically bolted to a flange mounted to the floor and coupled to the drain pipe. Toilet installations can include a gasket, usually a wax or rubber ring, disposed between the drain pipe and the toilet to produce a liquid-tight seal between the drain pipe and the toilet. For example, a wax ring can be coupled to the discharge outlet portion of the toilet by pressing the wax ring onto the discharge outlet portion, thereby deforming the wax ring to the contour of the discharge outlet portion. The toilet is then set on the flange such that the wax ring is axially aligned with the flange. Applying downward pressure on the toilet causes the wax ring to press onto the flange, thereby deforming the wax ring to the contour of the flange to produce the seal between the drain pipe and the discharge outlet portion of the toilet. A similar sealing process may be accomplished with a rubber ring or other types of gaskets.
A leak through the gasket seal can go undetected as the seal is obstructed from visual inspection by the toilet structure, typically the toilet base. A slow leak often does not extend a pool of water on the floor surface where the water may be detected by visual inspection. Rather a slow leak often allows water to seep into or under the floor deteriorating the floor structure and/or the ceiling structure underneath the floor. Water damage and mold growth in a ceiling underneath a toilet can be the first sign of a leak in the gasket seal.
Various leak detectors have been developed to address the problem of leaks in piping connections that are in visually obstructed locations such as a toilet seal with a drain pipe. Examples of such leak detectors are disclosed in the following patent documents: JP2008128666(A) by Shimura et al, JP7294367(A) Higuchi et al, JP2008163661(A) by Maruyama et al, JP2007218884(A) by Hiraide et al, U.S. Pat. No. 6,128,947 by Anderson, US2005160963(A1) by Siikaluoma et al, U.S. Pat. No. 3,485,085 by Hawkins, U.S. Pat. No. 5,461,904 by Baker, and US20110209278(A1) by Hatt. However, none of these leak detectors have achieved common acceptance.
Furthermore, most existing leak detectors are susceptible to yielding a false positive or a false negative signal. A false positive signal occurs when a detected liquid is an exogenous liquid and not the target liquid flowing through a piped connection. For example, when liquids are used to wash structures or surfaces proximal to a piped connection, a signal due to the washings would be a false positive signal. A false negative signal can arise when a leak is sufficiently slow that the liquid evaporates prior to contacting a liquid sensor in a leak detector.
Accordingly, there is a continuing need for alternative leak detectors for piping connections in visually obstructed locations where leaks cannot be readily determined by visual inspection.